Stealth 993

I got a question, do our cars have a clutch type LSD or is it a gear type?

If your suspension is setup up for it, a LSD will make you faster & safer! Plus it's the old school traction control!

chris walrod

Clutch plate type actuated by ramps via torque.

Stealth 993

Humm, well at least I don't have to worry about wheel lift. I can hit the FIA humps on the local track (early apex, cut in hard), it's slower, but a lot of fun to get some air around 90mph!

Another dumb question, the trans & rear diff share the same fluid? If so, we should be changing it more then the 50k recommended from Porsche? It's on my short list, as I'm pretty sure the "break in fluid" is still in there, or it's only been changed at the 30k maintaince.

chris walrod

Yep, same fluid. Change it every 15K -- if you track a lot, change it yearly. Look for chunks in the oil, pray for none.

I change mine every other engine oil change.

Schnell 911

Bacon? T your killing, I want LSD........:0

HJK

Have a look here, they're in the USA also, around 800 pounds or so, think thats like 1500 usd. www.quaife.co.uk , they have even for the tiptronic.... G'luck

Terry Adams

When I searched prior to rebuiliding my OEM LSD or replacing it with a Guard, I learned that Quaife was not the right way to go with our cars. Forgot why.

Mark in Baltimore

Quaifes aka Torsen aka torque sensing differentials don't have any lockup under braking, but they last far longer than clutch plate diffs since they use gears and not clutch plates.

chris walrod

Mostly because of the lack of trailing throttle or decel lockup abilities. They are quite aggressive on accel lock as well. Much like a light switch.

John H

If you've ever gone hard into a corner and felt the back end wiggle or dance under braking, you'll quickly realize the major difference of a working non-torque biasing limited slip differential. It won't do that anymore.

Also, at MO or other tracks with similar corners, you can get on the power harder and earlier coming out of Carousel and Keyhole without spinning the inside (right) tire or waiting for it to hook up.

Martin S.

and within 11 minutes after the original post, pesky Chris beats me to the punch

Just kidding, Chris' posts are invaluable, based on lots of real world race car experience.

When you install your LSD, or rebuild your factory unit, you may notice some understeer (push), that was not there before. Either learn to live with it or dial it out with a sway bar adjustment, assuming you have a adjustable sway bars. When I was Mr. M030 (RoW) before the current PSS-9 and TRG set up, I used a 22mm front bar with the 993TT RoW 21mm rear bar with an added drop link connection hole forward of the stock connection hole, to stiffen up the bar if needed. This was an ANDIAL trick.

chris walrod

Actually, Mark beat us all

Mark in Baltimore

The extra understeer will help with real trail-braking (not simply braking while turning).

Martin S.

Re. the above question, "Was the motorsport version available on standard cars?"

I don't believe it was. We get the 25/65...25% lock up on acceleration, 65% on deceleration. Couple this with your LSA rear suspension and AMS..plus the excellent Porsche brakes...great package!

Bill Verburg

G50/20 & 21 equipped 993s came w/ either an open diff or a ZF 25/65 or a GKN 22/40. option code M220

Only the M001 RS Cup w/ g50/30, M002 RS w/g50/31, M003 RSCS w/ G50/32, M002 RS for Switz. w/ g50/33 used the more robust GKN 40/65